摘要
采用等体积浸渍法制备了Al2O3、CeO2、TiO2及MgO负载Ni催化剂,考察了它们对甘油蒸汽重整制氢反应的催化性能。采用X射线衍射、N2吸附、透射电镜及H2程序升温还原等方法对催化剂进行了表征。结果表明,载体对Ni催化剂的活性有显著影响。在400℃下Ni/CeO2的催化活性明显好于其他催化剂,活性次序为Ni/CeO2〉Ni/Al2O3〉Ni/TiO2~Ni/MgO。Ni/CeO2也具有好的稳定性,反应20h未见活性下降,甘油转化率70%,氢气收率69.2%。这与CeO2的本性及其与活性组分的相互作用有关。Al2O3具有较大的比表面积与孔体积,有利于CO吸附及甲烷化反应的进行,使得Ni/Al2O3催化剂在较高温度下具有很高的甘油转化率85.7%,但H2选择性较差。由于MgO载体与活性组分强的相互作用而生成NiMgO2固溶体,导致Ni/MgO低温活性差。
Al2O3,CeO2,TiO2 and MgO supported Ni catalysts were prepared by incipient impregnation. The activities in glycerol steam reforming to hydrogen production were evaluated at 300 ~ 500 ℃. The catalysts were characterized by XRD,N2 adsorption,TEM,and H2-TPR techniques. A strong effect of support on the activity of Ni catalyst was detected. Ni / CeO2 catalyst gives the highest activity among all catalysts at 400 ℃ and the following activity order is shown Ni / CeO2 〉Ni / Al2O3〉 Ni / TiO2~ Ni / Mg O. On Ni / CeO2,there was almost no deactivation detected after 20 h reaction with 70% conversion of glycerol and 69. 2% H2 yield. Good activity and stability of the catalyst is attributed to the intrinsic property of CeO2 and strong interaction between CeO2 and active nickel species. Relatively high glycerol conversion（85. 7%） with lowH2 selectivity on Ni / Al2O3 catalyst at 500 ℃ is achieved due to its high surface area and large pore volume. The formation of solid solution Ni MgO2 phase observed in Ni / Mg O catalyst does not showthe desired activity at lowtemperatures though it enhanced the interactions between active phase and the support. Base oxide supports（ CeO2,Mg O） seem to be more effective than acid oxide supports in preventing the formation of CO and CH4 as by-products.
出处
《燃料化学学报》
EI
CAS
CSCD
北大核心
2015年第6期684-691,共8页
Journal of Fuel Chemistry and Technology
基金
国家自然科学基金(21273193)
山东省自然科学基金(ZR2011BM024)
关键词
甘油
蒸汽重整
制氢
负载Ni催化剂
glycerol
steam reforming
hydrogen production
supported nickel catalyst
